A comparative study on nanocrystalline soft magnetic Fe-Si-B-Nb-Cu alloys made of pure elements and ferro-alloys

•A process developed: Nanocrystalline FeSiBNbCu alloy using commercial grade master alloys.•Flux-shielded air induction melting process purifies the alloy by preventing oxidation and removing impurities.•Impurities present in the commercial grade alloy does not affect the glass forming ability.•Commercial grade alloy: Amorphous phase TC was found to decrease due to the impurities present.•The soft magnetic properties remain almost same for both alloys prepared using pure elements and commercial grade alloys.